1. Field of the Invention
The present invention generally relates to a method for forming a device isolation film of a semiconductor device, and more specifically to a method for forming a device isolation film of a semiconductor device wherein a predetermined region of a semiconductor substrate is etched to form a trench and a Selective Epitaxial Growth (“SEG”) silicon layer is formed in the trench to enhance the characteristic of semiconductor device.
2. Description of the Related Art
FIGS. 1a through 1g are cross-sectional views illustrating a conventional method for forming device isolation film of semiconductor device.
Referring to FIG. 1a, a pad oxide film 110 and a pad nitride film 120 are sequentially deposited on a semiconductor substrate 100.
Referring to FIG. 1b, a predetermined region of the pad nitride film 120, the pad oxide film 110, and the semiconductor substrate 100 is etched to form a trench 130.
Referring to FIG. 1c, a sidewall oxide film 140 is formed on a surface of the trench 130.
Referring to FIG. 1d, a liner oxide film 150 and a liner nitride film 160 are sequentially deposited on the entire surface of the semiconductor substrate including the trench 130.
Referring to FIG. 1e, a HDP oxide film 170 is deposited to fill up the trench 130.
Referring to FIG. 1f, a planarized process is performed via a CMP process to expose the pad nitride film 120.
Referring to FIG. 1g, the pad nitride film 120 is removed to form a device isolation film 170.
As described above, in accordance with the conventional method for forming device isolation film of semiconductor device, a predetermined region of a semiconductor substrate is etched to form a trench and the trench is filled up with a HDP oxide film to form a device isolation. However, while the depth of the trench is maintained, the width of the trench is reduced as the size of the semiconductor device is decreased, i.e. the aspect ratio of the device isolation film is increased. As a result, a void is generated in formation of the gap-fill insulating film, thereby degrading the barrier characteristic of the device.